Study on the Fracture Resistance of Mixed Fiber Concrete Lining in a Reverse Fault Tunnel.

With the increasing complexity of engineering environments in tunnel construction, some projects are located in areas with adverse geological conditions, including areas prone to fault movements and other geological hazards. Fiber-reinforced concrete can significantly enhance structural performance in such challenging conditions. Currently, the application of high-performance steel-polypropylene fiber in tunnel linings and its anti-fault performance are quite limited. Therefore, this paper focuses on studying the application of steel-polypropylene mixed fiber-reinforced concrete in tunnel lining under reverse fault movements. In this paper, the constitutive relationship of mixed fiber-reinforced concrete is modified based on literature data. Utilizing the Najar formula, fiber-related variables were designed, and a three-dimensional numerical simulation model of a reverse fault tunnel was established. By designing various parameter combination cases, the structural response of tunnel linings was calculated and studied. then the influence patterns of mixed fiber parameters on the anti-fault performance of tunnel linings are summarized, the relationships between main variables are explored, and a reasonable value range for the two fibers is determined, which can provide guidance for practical engineering. [ABSTRACT FROM AUTHOR]